Non-directional intra prediction for L-shape partitions

1. A method of video decoding in a decoder, comprising:

decoding prediction information of a current block in a current picture that is a part of a coded video bitstream, the prediction information indicating a non-directional intra prediction mode for the current block;

partitioning the current block into a plurality of partitions, the plurality of partitions including at least one L-shaped partition; and

reconstructing one of the plurality of partitions based on at least one of (i) neighboring reconstructed samples of the one of the plurality of partitions or (ii) neighboring reconstructed samples of the current block,

wherein the one of the plurality of partitions is an L-shaped partition and a number of the neighboring reconstructed samples is one of (i) a sum of a width and a height of the L-shaped partition, (ii) a sum of a shorter width and a shorter height of the L-shaped partition, (iii) a maximum value of the width and the height of the L-shaped partition, or (iv) a minimum value of the width and the height of the L-shaped partition.

2. The method of claim 1 , wherein at least one of the neighboring reconstructed samples is located in another one of the plurality of partitions that is reconstructed prior to the one of the plurality of partitions.

3. The method of claim 2 , wherein the another one of the plurality of partitions is an L-shaped partition, and the at least one of the neighboring reconstructed samples is located adjacent to one of a right side or a bottom side of the one of the plurality of partitions.

4. The method of claim 1 , wherein the neighboring reconstructed samples include a left column and a right column of the neighboring reconstructed samples of the one of the plurality of partitions, and the reconstructing includes:

determining a bottom row of neighboring reference samples of the one of the plurality of partitions based on the left column and the right column of the neighboring reconstructed samples of the one of the plurality of partitions; and

reconstructing the one of the plurality of partitions based on the bottom row of the neighboring reference samples of the one of the plurality of partitions.

5. The method of claim 1 , wherein the neighboring reconstructed samples include a top row and a bottom row of neighboring samples of the one of the plurality of partitions, and the reconstructing includes:

determining a left column of neighboring reference samples of the one of the plurality of partitions based on the top row and the bottom row of the neighboring reconstructed samples of the one of the plurality of partitions; and

reconstructing the one of the plurality of partitions based on the left column of the neighboring reference samples of the one of the plurality of partitions.

6. The method of claim 1 , wherein the reconstructing includes:

reconstructing the one of the plurality of partitions based on a left column and a top row of the neighboring reconstructed samples of the current block.

7. The method of claim 1 , wherein the reconstructing includes:

determining, for each sample of the L-shaped partition, a plurality of neighboring reference samples based on a position of the respective sample; and

reconstructing each sample of the L-shaped partition based on the plurality of neighboring reference samples of the respective sample.

8. The method of claim 7 , wherein the plurality of neighboring reference samples of each sample includes a reconstructed neighboring sample and a neighboring sample to be reconstructed based on the reconstructed neighboring sample.

9. An apparatus, comprising:

processing circuitry configured to

decode prediction information of a current block in a current picture that is a part of a coded video bitstream, the prediction information indicating a non-directional intra prediction mode for the current block;

partition the current block into a plurality of partitions, the plurality of partitions including at least one L-shaped partition; and

reconstruct one of the plurality of partitions based on at least one of (i) neighboring reconstructed samples of the one of the plurality of partitions or (ii) neighboring reconstructed samples of the current block,

wherein the one of the plurality of partitions is an L-shaped partition and a number of the neighboring reconstructed samples is one of (i) a sum of a width and a height of the L-shaped partition, (ii) a sum of a shorter width and a shorter height of the L-shaped partition, (iii) a maximum value of the width and the height of the L-shaped partition, or (iv) a minimum value of the width and the height of the L-shaped partition.

10. The apparatus of claim 9 , wherein at least one of the neighboring reconstructed samples is located in another one of the plurality of partitions that is reconstructed prior to the one of the plurality of partitions.

11. The apparatus of claim 10 , the another one of the plurality of partitions is an L-shaped partition, and the at least one of the neighboring reconstructed samples is located adjacent to one of a right side or a bottom side of the one of the plurality of partitions.

12. The apparatus of claim 9 , wherein the neighboring reconstructed samples include a left column and a right column of the neighboring samples of the one of the plurality of partitions, and the processing circuitry is further configured to:

determine a bottom row of neighboring reference samples of the one of the plurality of partitions based on the left column and the right column of the neighboring reconstructed samples of the one of the plurality of partitions; and

reconstruct the one of the plurality of partitions based on the bottom row of the neighboring reference samples of the one of the plurality of partitions.

13. The apparatus of claim 9 , wherein the neighboring reconstructed samples include a top row and a bottom row of neighboring samples of the one of the plurality of partitions, and the processing circuitry is further configured to:

determine a left column of neighboring reference samples of the one of the plurality of partitions based on the top row and the bottom row of the neighboring reconstructed samples of the one of the plurality of partitions; and

reconstruct the one of the plurality of partitions based on the left column of the neighboring reference samples of the one of the plurality of partitions.

14. The apparatus of claim 9 , wherein the processing circuitry is further configured to:

reconstruct the one of the plurality of partitions based on a left column and a top row of the neighboring reconstructed samples of the current block.

15. The apparatus of claim 9 , wherein the processing circuitry is further configured to:

determine, for each sample of the L-shaped partition, a plurality of neighboring reference samples based on a position of the respective sample; and

reconstruct each sample of the L-shaped partition based on the plurality of neighboring reference samples of the respective sample.

16. A non-transitory computer-readable storage medium storing instructions which when executed by at least one processor cause the at least one processor to perform:

decoding prediction information of a current block in a current picture that is a part of a coded video bitstream, the prediction information indicating a non-directional intra prediction mode for the current block;

partitioning the current block into a plurality of partitions, the plurality of partitions including at least one L-shaped partition; and

reconstructing one of the plurality of partitions based on at least one of (i) neighboring reconstructed samples of the one of the plurality of partitions or (ii) neighboring reconstructed samples of the current block,

wherein the one of the plurality of partitions is an L-shaped partition and a number of the neighboring reconstructed samples is one of (i) a sum of a width and a height of the L-shaped partition, (ii) a sum of a shorter width and a shorter height of the L-shaped partition, (iii) a maximum value of the width and the height of the L-shaped partition, or (iv) a minimum value of the width and the height of the L-shaped partition.